Azacitidine

Azacitidine is a nucleoside analogue. Azacitidine is a chemical analogue of cytidine. After entering the cell, it is phosphorylated by uridine-cytidine kinase to form 5-azacytidine monophosphate, then converted by pyrimidine monophosphate kinase into 5-azacytidine diphosphate, and finally converted by pyrimidine diphosphate kinase into 5-azacytidine triphosphate.

The actions of 5-azacytidine triphosphate mainly occur through two pathways. First, part of azacitidine is converted in the body into 5-azadeoxycitidine triphosphate and incorporated into DNA, where it forms covalent complexes with DNA methyltransferases (DNMTs) and inhibits their activity. This reduces DNA methylation and promotes re-expression of previously silenced tumor suppressor genes. Second, 5-azacytidine triphosphate can be incorporated into RNA, leading to abnormalities in RNA and protein synthesis as well as inhibition of cell growth.